Fraunhofer ISE's latest study: Hygrothermal DH and UV-UV attenuation mechanisms in TOPCon PV modules,TOPCon,

Crystalline Silicon Solar Cells Cleaning and Texturing Diffusion Junction Formation Coating Grid Line Characterization Solar Cell QC Inspection IEC Quality Testing Standards Module QC Inspection Perovskite Solar Cells Perovskite Online Detection Power Station Maintenance Monitoring

Quantum Efficiency Tester PL/EL Integrated System

PV-Reflectumeter 3D Confocal Microscope

In-Line Four Point Probe Tester Four Point Probe Tester In-Line Thin Film Thickness Tester Raman Spectrometer FTIR Spectrometer

Spectrophotometer Automatic Spectroscopic Ellipsometer

Contact Resistance Tester Ultra depth of field 3D microscope Auto Visual Tester VMM PV Vision Measuring Machine Solar Cell Horizontal Tensile Tester

Steady State Solar Simulator for Solar Cell Solar Cell UV Aging Test Chamber Solar Cell Comprehensive Tensile Tester IVEL Cell Sorting Machine

Visual Inspection Tester Wet Leakage Current Tester PV Module EL Tester PV Module UV Preconditioning Chamber Steady State Solar Simulator for PV Module Current Continuous Monitor Potential Induced Degradation Test Bypass Diode Tester LeTID Test System Reverse Current Overload Tester Impulse Voltage Tester Hipot Insulation Tester Ground Continuity Tester Hipot Insulation Ground Tester Damp Heat Test Chamber Humidity Freeze Test Thermal Cycle Test Chamber Dynamic Mechanical Load Tester Static Mechanical Load Tester Hail Impact Tester Robustness of Termination Tester Module Breakage Tester Cut Susceptibility Tester Peel Shear Strength Tester

Universal Testing Machine (Single-arm) Universal Testing Machine (Double-arm) Glass Transmittance Tester Acetic Acid Test Chamber EVA Degree of Crosslinking Test System Junction Box Comprehensive Tester Drop ball tester IV Tester

Semi-automatic scanning four-probe tester Stylus Profilometer Maximum Power Point Tracker

Perovskite Glass Transmittance Tester Perovskite P1 Laser Scribing Multifunctional Testing Machine Perovskite Online PL Tester Perovskite Online Sheet Resistance Tester Online Perovskite Film Thickness Tester Perovskite Process Inspection Workstation

Portable IV Curve Tester Portable EL Tester Portable Thermal Imaging Tester Solar Module Multi-Channel Testing System PV Inverter Power Quality Tester Drone EL Tester

Quantum Efficiency Tester

The MNPVQE-300Pro quantum efficiency tester is a common tool in photovoltaic research and production line quality processes, used for accurately determining the spectral response/EQE (IPCE) and IQE of solar cells.

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PL/EL Integrated System

Offering high-precision detection of internal defects in crystalline silicon solar cells, such as crystal defects and impurities. This enables production personnel to promptly adjust process parameters and improve product quality.

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PV-Reflectumeter

The RTIS Matte Reflectance Tester can measure the reflectance intensity of textured surfaces at different wavelengths. The test results are processed by software to calculate the photoelectric signals, ultimately presenting them as visual curves, which facilitates users in systematically characterizing the reflectance properties of the textured surfaces.

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3D Confocal Microscope

The ME-PT3000 is a specialized optical instrument for detecting the surface quality of photovoltaic (PV) cells. Based on optical principles, it combines a precision Z-axis scanning module with 3D modeling algorithms to achieve non-contact 3D scanning and imaging. This allows for the quantitative measurement of busbar height/width and the number of textured pyramids, providing feedback on the quality of cleaning, texturing, and screen printing processes.

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In-Line Four Point Probe Tester

FPP230 Auto is an In-Line Four Point Probe Tester specifically designed for “photovoltaic process monitoring.” It can quickly and automatically scan samples up to 230 mm in size, obtaining resistivity/resistance distribution information at different positions on the sample.

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Four Point Probe Tester

FPP230A is a automatic four point probe tester designed specifically for scientific research. It can quickly and fully automatically scan samples up to 230mm in size, obtaining resistivity/resistance distribution information from different locations on the sample.

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In-Line Thin Film Thickness Tester

The POLY5000 is an in-line thin film thickness tester specifically designed for monitoring photovoltaic processes. It can perform rapid, automatic 5-point synchronous scanning of samples, monitoring the thickness and optical constants of various films on the "industrial production line". It provides fast and accurate measurements of film thickness, optical constants, and other information, with customizable measurement dimensions based on customer sample sizes.

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Raman Spectrometer

The Millennial Solar Galaxy Solar crystallization rate tester is suitable for both spectroscopy and imaging, featuring a high spectral resolution and extremely low stray light. This ensures the accuracy and repeatability of spectral data. A series of new technologies for Raman spectral imaging have been introduced, significantly enhancing the quality and speed of Raman spectral imaging. The novel imaging algorithms can extract useful spectral information from complex big data.

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FTIR Spectrometer

Fourier Transform Infrared Absorption Spectroscopy (FTIR) is a powerful tool for studying the relationship between the emission or absorption of radiation by various molecules in the infrared spectrum and their molecular structures. It is primarily used for the analysis of material structures.

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Spectrophotometer

The UVN2800-Pro spectrophotometer features a unique dual-beam optical design that effectively corrects for absorbance variations caused by different sample matrices, allowing for stable sample measurements. It offers a wide testing range, high precision, and excellent stability.

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Automatic Spectroscopic Ellipsometer

The UVPLUS SE Spectroscopic Ellipsometer is a high-performance, specialized spectral ellipsometer developed by Millennial Solar for the research and quality control of photovoltaic solar cells. It covers a wavelength range from ultraviolet to visible and near-infrared.

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Contact Resistance Tester

In the optimization of solar cell electrodes, contact resistance is an important aspect to consider. The magnitude of contact resistance is not only related to the contact geometry but also to the diffusion and sintering processes. Measuring contact resistivity can reflect issues present in the diffusion, electrode fabrication, and sintering processes.

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Ultra depth of field 3D microscope

The ME-UD6300 Ultra Depth-of-Field Microscope is a detection instrument designed for sub-micron level measurements of various precision components and material surfaces. It utilizes high numerical aperture objectives and apertures, adjusting the size of the light spot and the position of the aperture to achieve varying degrees of focus at different depths, thereby realizing the ultra depth-of-field effect.

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Auto Visual Tester

Millennial AVT-4030 Auto Visual Tester integrates size, defect, film thickness, and tension detection into one, achieving high precision, high efficiency, and comprehensive defect detection for photovoltaic screen printing, as well as line width, line spacing, and shrinkage measurement. It is the ideal quality inspection assistant for quality control (QC) personnel.

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VMM PV Vision Measuring Machine

Millennial Vision Measuring Machine equipped with a measurement system based on a high-resolution camera, allowing for fast and accurate measurement of various components.

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Solar Cell Horizontal Tensile Tester

In the photovoltaic industry, during the incoming material inspection of solar cells, bending tests and solder strip peel strength tests are conducted to evaluate the quality of the bus bar welding. The ME-CELL-HTT is a horizontal tensile testing machine specifically designed for 180° peel tests on solar cells.

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Steady State Solar Simulator for Solar Cell

The Millennial Steady State Solar Simulator for Solar Cell utilizes metal halide lamps that simulate full-spectrum light sources to replicate destructive light waves present in various environments. It provides corresponding environmental simulation and accelerated testing for photovoltaic solar cell product development and quality control.

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Solar Cell UV Aging Test Chamber

The Millennial Solar Cell UV Aging Test Chamber for Photovoltaic Solar Cells is a device specifically designed to simulate the ultraviolet radiation in the natural environment and conduct accelerated aging tests on photovoltaic solar cells.

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Solar Cell Comprehensive Tensile Tester

The Millennial Solar Cell Comprehensive Tensile Tester has a horizontal module testing function. It can conduct a horizontal 180° solder strip peel strength test, with 28 sensors in use simultaneously. It can also perform cell bending tests, meeting three point and four point bending test requirements.

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Visual Inspection Tester

Appearance defects of photovoltaic modules (such as cracks, bubbles, delamination, etc.) may intensify during subsequent tests and have an adverse impact on the performance of the modules.

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Wet Leakage Current Tester

Wet Leakage Current Tester is used to verify the influence of moisture caused by rain, fog, dew or melting snow on the circuit caused by corrosion, leakage or safety accidents,ensure that the insulation performance of the module complies with the standards.

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PV Module EL Tester

The EL tester for photovoltaic modules in the laboratory is a high-precision detection device based on the principle of electroluminescence (EL). It is mainly used to evaluate the internal defects and performance of photovoltaic modules, ensuring the product quality and reliability.

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PV Module UV Preconditioning Chamber

The Millennial PV Module UV Preconditioning Chamber for photovoltaic modules is a specialized device used to simulate the ultraviolet radiation in the natural environment and conduct accelerated aging tests on photovoltaic modules.

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Steady State Solar Simulator for PV Module

The Millennial Steady State Solar Simulator uses metal halide lamps that can simulate full - spectrum light sources to reproduce the destructive light waves present in different environments. It can provide corresponding environmental simulation and accelerated tests for the product development and quality control of photovoltaic modules.

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Current Continuous Monitor

The current continuity test system is for IEC61215 standard 10.11 high and low temperature cycle experiment clause, 10.12 wet freezing experiment clause. Mainly includes the provision of stable direct current, current recording, temperature recording and temperature control functions, through the temperature control of the DC power supply, the multi-channel current, multi-channel temperature long-term real-time monitoring.

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Potential Induced Degradation Test

Long-term leakage current will cause changes in the state of the cell carriers and depletion layer,corrosion of the contact resistance in the circuit,and electrochemical corrosion of packaging materials.This results in cell power attenuation,increased series resistance,reduced light transmittance,delamination and other phenomena that affect the long-term power generation and life of the module.

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Bypass Diode Tester

The Bypass Diode Tester is a core inspection device specifically designed for photovoltaic modules, which is used to evaluate the conduction performance, thermal stability, and durability of bypass diodes under extreme operating conditions. As the "safety valve" of photovoltaic modules, bypass diodes can effectively prevent the hot spot effect and ensure that the modules can still operate safely when there is partial shading or when solar cells fail.

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LeTID Test System

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Reverse Current Overload Tester

During the application of solar cells, due to voltage drops, they may be reversely charged by other cell strings. If the reverse charging current does not reach the protection current of the cell string fuse, the module may be reversely charged for a long time, with the temperature continuously rising, thus damaging the module.

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Impulse Voltage Tester

The Millennial Impulse Voltage Tester is a key device specifically designed to evaluate the insulation performance and reliability of photovoltaic modules under transient overvoltage conditions such as lightning strikes and switching surges.

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Hipot Insulation Tester

The photovoltaic hipot insulation tester is a specialized device used to evaluate the insulation performance and withstand voltage capability of photovoltaic modules and electrical equipment. It mainly detects the leakage current, insulation resistance, and withstand voltage strength of these components in a high-voltage environment to ensure that the products meet the safety standards and prevent the risks of fires or equipment damage caused by insulation failures.

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Ground Continuity Tester

The Ground Continuity Tester is a key device specifically designed to evaluate the reliability of the grounding system of photovoltaic modules. Its main function is to detect the resistance value between the metal frame of the photovoltaic module, the junction box, and the grounding conductor, ensuring that the grounding continuity meets the safety standards.

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Hipot Insulation Ground Tester

ME-PV-HIG developed by Millennial Solar for photovoltaic industry automated testing systems, the ME-PV-HIG combines withstand voltage testing, insulation resistance measurement, and ground continuity verification in one advanced device. Standard with data acquisition software and supporting remote firmware updates via USB, it fully complies with photovoltaic standards IEC 61215 and IEC 61730.

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Damp Heat Test Chamber

Solar modules must withstand harsh climatic conditions during application. Among these, the high-temperature and high-humidity environment (DH test) is a core testing item for evaluating photovoltaic module reliability and material durability.

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Humidity Freeze Test

During the application process of solar modules, they will be subjected to the tests of various harsh weather conditions. Among them, the performance of the modules, such as their ability to withstand high temperature and high humidity as well as the subsequent impact of low temperature, and their ability to withstand long-term moisture penetration, needs to be evaluated. The HF test is carried out to verify and evaluate the reliability of the modules or materials, and to identify manufacturing defects at an early stage by inducing failure modes through thermal fatigue.

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Thermal Cycle Test Chamber

The Millennial Thermal Cycle Test Chambe is a reliability testing device specifically designed for solar modules. It accurately simulates a rapidly alternating environment of high and low temperatures to verify the performance, structural stability, and long-term durability of module products under extreme temperature conditions. Moreover, by inducing failure modes through thermal fatigue, it helps users detect potential defects in advance, thus improving product quality and market competitiveness.

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Dynamic Mechanical Load Tester

Mechanical performance assessment is required for both photovoltaic (PV) modules and building - integrated photovoltaic (BIPV) systems. This assessment is a crucial step in ensuring the long - term functionality of these systems and optimizing commercial products. Performance tests are carried out through methods such as mechanical loading (ML), inhomogeneous mechanical loading (IML), and dynamic mechanical loading (DML) to verify the performance of PV modules under external mechanical loads, ensuring that the modules are free from visual damage and significant loss of electrical functionality.

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Static Mechanical Load Tester

The static mechanical load tester for photovoltaic modules is a specialized device used to simulate the static mechanical loads (such as wind pressure, snow pressure, ice accumulation, etc.) that photovoltaic modules bear during actual outdoor installation. By applying continuous pressure or tensile force, it evaluates the structural strength, material durability, and electrical performance stability of the modules.

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Hail Impact Tester

During the operation of a photovoltaic (PV) system, PV modules face various environmental challenges, including hail. When hailstones strike the surface of PV modules at high speed, they may cause serious impacts such as surface damage, cell damage, and broken connection wires. Therefore, understanding the impact of hail on PV modules and the modules' impact - resistance capabilities is crucial for ensuring the reliability and durability of the PV system.

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Robustness of Termination Tester

This test is for IEC61215 standard MQT14 in the design and development of the leading end strength test system, testing machine is divided into tensile testing machine, torsion testing machine, adhesion testing machine 3 products.

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Module Breakage Tester

The module breakage tester is a specialized testing equipment dedicated to evaluating the impact resistance performance of photovoltaic modules (especially BIPV). Its core function is to simulate the scenarios of the glass surface being impacted by the human body or objects, and verify the safety of the modules under extreme mechanical loads.。

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Cut Susceptibility Tester

Solar panels have plastic materials on their surface. During any process of production, installation, and operation, they may be scratched when touched by sharp objects, affecting the insulation of the panels. In severe cases, the internal charged parts will be exposed, resulting in the risk of electric shock.

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Peel Shear Strength Tester

Peel Shear Strength Tester is an innovative dual-function equipment developed through years of PV product testing and research, specifically designed for both peel testing and adhesion testing of photovoltaic modules. Its technical specifications fully comply with the requirements of IEC 61730-2:2016 standards.

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Universal Testing Machine (Single-arm)

The Millennial Universal Testing Machine (Single-arm) adopts a compact single-column design. Tailored for the small-load, high-precision testing demands of photovoltaic materials, it is ideal for key components such as solder strips, encapsulation films, and junction box connectors.

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Universal Testing Machine (Double-arm)

The Millennial Universal Testing Machine（Double-arm is a high-precision and high-stability mechanical testing device. Centered around a double-column gantry structure, it features high stability and large load-bearing capacity. It is specifically designed for verifying the strength of materials such as PV glass, aluminum alloy frames, and backsheets.

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Glass Transmittance Tester

Glass Transmittance Tester PGT2400 is a powerful tool for photovoltaic glass performance testing. It has high-precision measurement accuracy and stability. It can measure the transmittance of the sample, calculate the AM1.5 effective solar transmittance, visible light transmittance, Y, x, y, L*, a*, b* and other color parameters of ultra-white embossed glass, and display CIE color coordinates and chromaticity diagrams.

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Acetic Acid Test Chamber

Photovoltaic modules usually use EVA (ethylene-vinyl acetate copolymer) adhesive film to encapsulate solar cells. During the long-term exposure and use outdoors, in addition to the erosion of water vapor, the EVA adhesive film will also degrade to generate acetic acid and olefins. The escaped acetic acid can corrode the electrode grid lines, solder ribbons, etc. of the solar cells, affecting the output power and safety performance of the photovoltaic modules.

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EVA Degree of Crosslinking Test System

Degree of cross-linking Test System is used to test materials such as EVA cross-linking, polyethylene (PE cross-linking,polyethylene insulated wire and cable (XLPE) cross-linking,natural polymer ion cross-linking and polymer crystallinity for photovoltaic module encapsulation. Test its flexibility, impact resistance, elasticity, optical transparency, low temperature bending, adhesion, environmental stress cracking resistance,weather resistance, chemical resistance, and heat sealing.

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Junction Box Comprehensive Tester

The ME - 9960 junction box comprehensive tester is a dedicated testing instrument developed by our company to meet the testing requirements for the electrical characteristics of photovoltaic junction boxes. It can test parameters such as the forward conduction voltage drop VF, reverse leakage current IR, reverse voltage VR, on-state DC resistance R, and temperature TC of the diodes inside the junction box.

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Drop ball tester

The Millennial Drop Ball Tester adjusts a steel ball of a specified weight to a certain height and allows the steel ball to fall freely for the test. It impacts the surface of the test specimen and observes the degree of damage, which is used to determine the quality of plastics, ceramics, acrylics, glass fibers, photovoltaic modules, tempered glass and junction boxes.

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Semi-automatic scanning four-probe tester

The FPP300SA is a semi-automatic four-point probe sheet resistance tester designed for scientific research. It enables fast and precise testing of samples up to 450mm x 400mm, providing sheet resistance/resistivity information at different locations. The probe head incorporates precision mechanical clock movement technology, utilizing ruby bearings to guide tungsten carbide probes, ensuring high mechanical accuracy and extended durability. Industry-leading repeatability of 0.2% is achieved for standard resistor testing.

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Stylus Profilometer

The Millennial Stylus Profilometer adopts contact - based surface topography measurement. It can measure the profiles of sample surfaces on scales ranging from micrometers to nanometers, and is capable of measuring step height, film thickness and thin - film height, surface topography, surface waviness, surface roughness, etc. It represents a new development in traditional surface topography measurement.

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Maximum Power Point Tracker

Millennial Maximum Power Point Tracker is a powerful and comprehensive multi-channel solar cell and component stability test system tailored for perovskite solar cell researchers. It uses a BBA-level LED solar simulator as an aging light source. It can control the temperature of the battery and the environmental atmosphere of the battery in a variety of ways (N2, dry air, constant temperature and humidity, etc.).

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Perovskite Glass Transmittance Tester

The online transmittance detection equipment for perovskite solar cells is a system that real - time monitors the optical transmittance of perovskite thin films, transparent oxide glass, or modules. It is used to optimize processes, ensure uniformity, and improve cell efficiency.

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Perovskite P1 Laser Scribing Multifunctional Testing Machine

After the deposition of the transparent conductive electrode (TCO) and before the deposition of the hole - transport layer, a laser device will perform laser scribing on the sample to form independent strip - shaped conductive electrodes, which will serve as positioning points for subsequent P2 and P3 scribing. Therefore, by conducting quality inspections on P1 scribing, the efficiency, stability, uniformity, lifespan, safety, and manufacturing cost - effectiveness of perovskite solar cells can be improved in multiple aspects.

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Perovskite Online PL Tester

Online PL defect detection addresses core challenges in solar cell production—speed, yield, cost, process optimization, and stability—through its non-contact, high-precision, and real-time feedback capabilities. Integrated with AI-driven deep learning, it enables fully automated defect identification and process optimization. This empowers customers to refine manufacturing parameters based on test results, enhancing device efficiency and stability.

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Perovskite Online Sheet Resistance Tester

The online sheet resistance tester is a critical quality control device for perovskite solar cell production lines, designed to monitor the sheet resistance of materials such as transparent conductive layers in real time. Utilizing four-probe technology, it enables high-speed detection of thin-film conductivity uniformity, ensuring stable series resistance and fill factor, thereby enhancing the photovoltaic conversion efficiency of cells.

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Online Perovskite Film Thickness Tester

The online thickness measurement system utilizes spectroscopic ellipsometry principles. It analyzes alterations in the polarization state of linearly polarized light after reflection from thin-film samples. By measuring phase differences and amplitude ratios, film thickness is derived through model fitting. Featuring non-destructive testing capabilities, it preserves delicate film integrity while adapting to both wet-processing techniques (slot-die coating, inkjet printing) and vacuum deposition applications.

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Perovskite Process Inspection Workstation

The Perovskite Process Inspection Workstation integrates a Contact Angle Test Module, an Ellipsometer Test Module, a Sheet Resistance Test Module, and a Reflectance Test Module, facilitating users to conduct comprehensive evaluations of photovoltaic films. This all-in-one testing machine supports manual click/auto-switching of test modules. During testing, it enables single-point positioning mapping (supporting up to 5,000 points) and single-point multi-technique measurement (multifunctional testing for single points), maximizing one-stop service for customers.

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Portable IV Curve Tester

This portable PV module power tester accurately measures the power output and IV curve of individual solar modules, while providing standardized power conversion efficiency under STC (Standard Test Conditions). The system features intuitive operation, high portability, and is equipped with a precision irradiance meter and temperature sensor.

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Portable EL Tester

The portable EL tester is designed to detect hidden cracks inside solar panels, ensuring efficient power generation of photovoltaic modules. With a compact design, user-friendly operation, and high portability, it is ideally suited for mobile users requiring on-site inspections. This mobile testing tool is tailored for component inspection in solar power plants. 3 Core Strengths: High-Def Imaging, Intelligent Recognition, Portable Operation Adaptable to indoor/outdoor all-terrain inspection, it enables rapid & accurate identification of internal defects in diverse PV modules (e.g., c-Si, perovskite). By streamlining ops processes, boosting inspection efficiency, and cutting labor costs, it delivers reliable testing data for plant O&M—empowering teams to achieve refined management and minimize power generation losses.

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Portable Thermal Imaging Tester

This compact handheld infrared thermal imager is specifically designed for photovoltaic power plants to conduct temperature inspections on all electrical equipment. It helps identify potential faults, reduce maintenance costs, and ensure production safety.

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Solar Module Multi-Channel Testing System

The outdoor module multi-channel testing system provides real-time synchronous multi-channel testing capabilities and supports customization of channel quantity and test module power according to specific user requirements. By networking multiple testers, it forms an evaluation system capable of simultaneously testing up to 300 photovoltaic (PV) modules, making it ideal for outdoor PV module performance comparison. The system enables comparative testing of multi-channel power generation efficiency, allowing side-by-side evaluation of IV characteristics and energy yield differences across different modules on the same time base.

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PV Inverter Power Quality Tester

The PV inverter power quality tester provides detailed recording and analysis of power quality parameters at photovoltaic power plant sites, including harmonics, voltage, current, frequency, voltage fluctuations, flicker, power, and three-phase unbalance. It also features advanced measurement functions such as power transient monitoring, waveform recording analysis, energy efficiency loss assessment, and inverter performance measurement, providing accurate data for managing grid-connected power quality in PV power plants.

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Drone EL Tester

Designed for electroluminescence (EL) internal defect detection in PV power plant array components, this drone-based EL tester efficiently completes power plant quality inspection tasks. It supports switching between photo and video modes, facilitating third-party operation and maintenance (O&M) quality checks. Combined with fully automated focusing technology, the device enables flexible switching between multiple detection modes, making it the preferred tool for power plant inspection and O&M.

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IV Tester

It is mainly used to test the electrical properties of solar cells or modules. By testing the volt-ampere characteristic curve of solar cell or module, it can get its maximum power Pmax, maximum power point current Impp, maximum power point voltage Vmpp, short-circuit current Isc, open-circuit voltage Voc, fill factor FF (Fill Factor), photovoltaic conversion efficiency Eff, series resistance Rs, parallel resistance Rsh and other parameters.

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IVEL Cell Sorting Machine

Millennial IVEL Cell Sorting Machine is the core equipment of PV cell production line, designed for high efficiency cell performance classification (IV test) and defect detection (EL test), supporting data traceability to optimize the process, and significantly improving module yield and product value.

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Fraunhofer ISE's latest study: Hygrothermal DH and UV-UV attenuation mechanisms in TOPCon PV modules

Date : 25 July 2025Views : 1905

With PV plant lifetimes needing to exceed 20 years, reliability testing and quality assurance are critical, especially with respect to moisture ingress and resistance to ultraviolet (UV) radiation. International Electrotechnical Commission (IEC) standards (e.g. IEC 61215) provide guidelines for indoor accelerated aging tests, but the challenge lies in how to correlate with actual outdoor conditions.TOPCon technology is susceptible to moisture corrosion due to the silver-aluminum (Ag-Al) paste front surface metallization, and the SiNx passivation layer is prone to fracture of the Si-H bond under UV, leading to an increase in defect density. Among them, Millennial temperature and humidity integrated environmental test chamber can carry out indoor accelerated aging to meet the IEC61215 and other standards. In this study, we explore the attenuation mechanism of TOPCon, HJT, and PERC modules through indoor humid-heat DH aging and UV-UV aging combined with subsequent 8-month outdoor exposure.

Experimental Methods

Samples and Grouping

Three common bifacial PV modules on the market were selected: HJT (H1, H2), TOPCon (T1, T2, T3) and PERC (P1). The initial parameters of all samples were measured under laboratory standard test conditions (STC), covering key indicators such as maximum power (PMPP), open-circuit voltage (Voc), and short-circuit current (Isc).

PV module parameters (frontal exposure) and temperature coefficient of maximum power (TC PMPP) measured under laboratory STC

Experimental Design

Overview of the experimental procedure

Overview of the experimental procedure: (left) Damp heat aging experiment setup; (right) UV aging experiment setup. Green is standard test conditions (STC), blue is non-STC test, and orange is accelerated aging procedure.

Two sets of aging experiments are conducted, Damp Heat DH and UV UV. Four samples of each type of PV module were taken: two “new” samples (M01, M02) were subjected to STC and non-STC indoor characterization according to IEC 61853-1, and two samples (M03, M04) were subjected to accelerated aging with STC testing before and after aging. All samples were subsequently exposed outdoors for approximately 8 months (beginning of summer), during which time their IV curves were continuously monitored in MPP operation.

Indoor accelerated aging

Damp heat aging group according to IEC 61215-2 standard, test at 85℃, 85% RH condition for 2000 hours; UV aging group adopts the scheme modified from IEC 61730-2, 60 kWh/m² UV dose exposure.

Outdoor exposure

(left) Damp heat test setup in the outdoor performance laboratory of Fraunhofer ISE, Germany; (right) UV aging test setup.

The DH samples were mounted on an open stand (30° inclination) in Merdingen, Germany;

UV samples were placed on the roof of Freiburg (backside masked to simulate a single-sided assembly).

Data processing

Characterization parameters such as Isc, Voc, PMPP, FF and Rs were obtained from IV curves. The data was filtered to an irradiance range of 775-825 W/m² and normalized to 800 W/m² and 42.5°C to reduce measurement uncertainty.

Impact of Damp Heat Aging on Module Performance

DH aging test module first week outdoor performance (NP_MPP-0), dotted line box diagram for lab aging samples

Indoor DH aging tests show that the performance degradation of different types of modules varies. HJT (H1, H2) and TOPCon (T1) have larger PMPP degradation (2.5%-3%), mainly due to the decrease of FF and the increase of Rs, while the degradation of TOPCon (T2) and PERC (P1) is relatively slight (<2%).

T2, H1, P1 modules DH aging 2000h after 5 months outdoor appearance inspection

T2, H1, P1 modules DH aging 2000h after 5 months outdoor appearance inspection (visible edge discoloration and drip marks)

Outdoor exposure further reveals the long-term effects of moisture and heat aging: the aging samples of TOPCon (T1) show a continuous degradation of 9.75% in PMPP, a 9.4% decrease in FF, and an increase of about 20% in Rs in 8 months, and the EL image shows a clear dark zone at the edge of the samples, which confirms that corrosion degradation is triggered by the intrusion of moisture; and the performance of HJT (H2) is also declined due to the discoloration of the package and the increase of Rs caused by moisture intrusion. It is worth noting that the degradation of some brand new modules (e.g., H2, P1) after 8 months of outdoor exposure exceeds the indoor test results, suggesting that new degradation mechanisms may be activated by the complex outdoor environment.

Impact of UV Aging on Module Performance

TOPCon-T3 module first week outdoor performance (NPMPP-0), dashed box plot shows UV aged sample

TOPCon (T3) UV aging tests show a 2.5% drop in PMPP and a 1.5% drop in Voc after 60 kWh/m² of UV exposure, which correlates with degradation of the surface passivation layer. At the beginning of outdoor exposure (within 1 week), the difference in PMPP between aged and new samples is 2.4%, which is in line with the indoor results; as the exposure is prolonged, the Voc of the aged samples tends to stabilize under the natural day/night cycle, which confirms the “stabilizing effect” of the UV degradation in outdoor environments.

Evolution of Voc for all new TOPCon samples during outdoor exposure (with back masking differences)

In addition, the comparison of TOPCon components with different mounting methods reveals that the Voc degradation of the open bracket-mounted T1 and T2 components (without back shading) is up to 1%, while the Voc degradation of the back-shaded T3 component is less than 0.25%, suggesting that the backside UV radiation may be one of the degradation factors of the outdoor Voc, which needs to be further investigated.

This study proposes a combined indoor-outdoor measurement method for exploring the specific degradation mechanism of TOPCon modules and comparing it with heterojunction (HJT) and passivated emitter back contact (PERC) technologies. Modules were subjected to accelerated moisture-heat DH or UV-UV aging and then co-exposed outdoors with unaged samples. The methodology reveals the severity of moisture ingress and its effect on the increase in series resistance and decrease in fill factor, and identifies the drop in open-circuit voltage (VOC) during UV aging as the main cause of the performance degradation, while validating the stabilization behavior equivalent to day/night cycling in the laboratory.

Millennial Temperature and Humidity Comprehensive Environmental Test Chamber

email：market@millennialsolar.com

Millennial temperature and humidity integrated environmental test chamber adopts imported temperature controller, which can realize multi-stage temperature programming with high accuracy and good reliability to meet the testing needs under different climatic conditions.

Temperature range: 20℃~+130℃

Temperature and humidity range: 10%RH~98%RH(at+20℃-+85℃)

Meet the test standards: IEC61215, IEC61730, UL1703 and other testing standards

Millennial temperature and humidity integrated environmental test chamber can provide reliable indoor accelerated aging test, in line with IEC testing standards, for accurate simulation of hot and humid stress environment.